1,3-butadiene is an intermediate product of petroleum chemicals in a petrochemical market, and demands for 1,3-butadiene and its value are gradually increasing. Naphtha cracking, direct dehydrogenation of n-butene, and oxidative dehydrogenation of n-butene are known as a method of preparing such 1,3-butadiene. However, the naphtha cracking process which occupies 90% or more of 1,3-butadiene supplied to the market has shortcomings in that energy consumption is high due to a high reaction temperature and also other fractions in addition to 1,3-butadiene are redundantly produced because the naphtha cracking process is not an exclusive process only for the production of 1,3-butadiene. Furthermore, the direct dehydrogenation of n-butene is not suitable for a commercial process for the production of 1,3-butadiene because it is not only thermodynamically unfavorable but also endothermic and thus requires high-temperature and low-pressure conditions to produce 1,3-butadiene with high yield.
The oxidative dehydrogenation (ODH) of n-butene which produces butadiene through oxidative dehydrogenation of n-butene produces 1,3-butadiene by removing two hydrogen atoms from n-butene using oxygen as a reactant so that stable water is produced as a product. Thus, the ODH is very advantageous thermodynamically, and is exothermic contrary to the direct dehydrogenation, so that 1,3-butadiene can be obtained with high yield even at a low temperature compared with the direct dehydrogenation. Therefore, a process of producing 1,3-butadiene through the oxidative dehydrogenation of n-butene may be an effective and exclusive production process satisfying increasing demands for 1,3-butadiene. Therefore, studies on a method of producing 1,3-butadiene having high selectivity by improving efficiency through the oxidative dehydrogenation of n-butene are being carried out.
Under the aforementioned background, while studying a bismuth molybdate-based composite oxide catalyst having high selectivity for 1,3-butadiene, the present inventors completed the present invention by finding that a catalyst having a microporous zeolite coating layer on the surface thereof not only enables products to selectively pass through the zeolite coating layer to thereby have high selectivity for 1,3-butadiene, but also simplifies phases of products by discharging solid organic by-products as a gas phase, which makes it easy to perform a purification process on products.